Magnetic tape cartridge for housing a reel

ABSTRACT

A single reel with magnetic tape wound thereon is housed in a case. A restraining member, for restricting rotation of the reel by moving toward or away from the reel, is urged in a restraining direction by an urging member. The pushing-up portions of a releasing member are inserted into the through holes bored in the reel gear of the reel  2  so that the lower ends can abut a driving gear. The releasing member moves the restraining member in a releasing direction by moving according to the chucking operation of drive-side rotation drive means. In this manner, reel-rotation restraining means allows rotation of the reel when being used and restricts the rotation when not being used. In this construction, each of the through holes is bored between the tooth edges of the reel gear so that the releasing member can perform a reliable releasing operation.

TECHINICAL FIELD

[0001] The invention relates to a magnetic tape cartridge and moreparticularly relates, in a magnetic tape cartridge for rotatably housingwithin a cartridge case a single reel having magnetic tape woundthereon, to the structure of reel-rotation restraining means for causingthe reel to be in a rotation-restrained state when not being used.

BACKGROUND ART

[0002] In conventional tape cartridges used as storage media that areemployed in external storage units for computers, etc., there is known atype in which magnetic tape is wound on a single reel and this reel isrotatably housed within a cartridge case. This magnetic tape is employedas a data storing tape for computers, etc., and because importantinformation is stored, reel-rotation restraining means to restrictrotation of the reel is installed so that problems, such as tapejamming, etc., do not occur and so that the magnetic tape is notforwarded unexpectedly when not being used, such as when being archived,etc.

[0003] The reel-rotation restraining means is equipped with arestraining member that restricts rotation of the reel by engaging partof the reel, and is provided so that when the cartridge is loaded into adrive unit such as an external storage unit, etc., a restrained state bythe restraining member is released according to a reel chuckingoperation performed by drive-side rotation drive means.

[0004] Hence, due to demands for enhancement in the reliability of theaforementioned operation of the reel-rotation restraining means,prevention of dust entry into the cartridge, etc., this reel-rotationrestraining means is provided in a structure separated into arestraining member for restricting rotation of the reel, an urgingmember for urging this restraining member in a restraining direction,and a releasing member for moving the restraining member in a releasingdirection by moving in accordance with the chucking operation of thedrive-side rotation drive means.

[0005] That is, in the non-operative condition, the reel is restrictedby the restraining member so that it does not rotate unexpectedly, as aresult of which the magnetic tape is not forwarded. However, if thecartridge is loaded into a drive unit and chucking of the reel isperformed by rotation drive means, there leasing member moves ininterlock with the chucking operation and releases the restrainingmember. In this state, the reel is rotatable and therefore the magnetictape can be forwarded and rewound.

[0006] In the aforementioned mechanism, it is also preferable to performthe pushing operation, for the releasing movement of the releasingmember which results from the chucking operation of the drive-siderotation drive means, at a plurality of positions on the outerperipheral portion rather than at a single position on the centerportion, because a stable releasing operation can thus be performed. Atthis time, it is advantageous in achieving structural simplification,etc., to provide a reel gear, which meshes the driving gear of thedrive-side rotation drive means, in the reel, to provide pushing-upportions, formed in part of the releasing member, so that the distalends abut the driving gear through the through holes provided in thereal gear, and to provide the driving gear so that when the drive-siderotation drive means performs the chucking operation, the driving gearpushes the pushing-up portions and releases the releasing member.

[0007] However, piercing the reel gear and boring the through holes, asdescribed above, will reduce the mesh between the reel gear and thedriving gear and therefore become a problem with respect to driving thereel reliably. If the through hole is reduced from such a respect, theshape of the portion of the releasing member inserted into this throughhole will also become smaller and therefore there is a possibility thatit will become unstable for the tooth edge of the driving gear to abutthe reduced portion accurately and give a reliable pushing operation.

[0008] In addition, in the case where the pushing-up portions are formedin part of the releasing member and are inserted into the through holesof the reel and slid, as described above, the releasing member issubjected to the urging force of the urging member and gives rise tobending deformation. As a result, since a tilting force acts on thepush-up portion, part of the outside surface is pushed against the innersurface of the through hole and the friction resistance becomes greater,the sliding between the pushing-up portion and the through hole isdisturbed, and there is a possibility that the releasing member will notbe able to release the restraining member reliably.

[0009] The present invention has been made in view of theabove-mentioned points, and accordingly, the object of the invention isto provide a magnetic tape cartridge in which the releasing member ofthe reel-rotation restraining means is capable of performing a reliablereleasing operation.

DISCLOSURE OF THE INVENTION

[0010] To solve the aforementioned problems, there is provided amagnetic tape cartridge, for rotatably housing within a cartridge case asingle reel having magnetic tape wound thereon, comprising reel-rotationrestraining means for allowing rotation of the reel when being used andrestricting the rotation when not being used; wherein

[0011] the reel-rotation restraining means has a restraining member forrestricting rotation of the reel by moving toward or away from the reel,an urging member for urging the restraining member in a restrainingdirection, and a releasing member for moving the restraining member in areleasing direction, by rotating integrally with the reel and movingaccording to chucking operation of drive-side rotation drive means;

[0012] the reel is provided with a reel gear which meshes a driving gearof the drive-side rotation drive means, and a pushing-up portion formedin part of the releasing member is provided so that a distal end thereofcan abut the driving gear through a through hole provided in the reelgear; and

[0013] the through hole is bored between tooth edges of the reel gear.

[0014] Also, it is preferable that a recess engageable with a tooth edgeof the driving gear be formed in a distal end surface of the releasingmember which abuts the driving gear.

[0015] According to a magnetic tape cartridge such as theaforementioned, the through hole which is provided in the reel gear ofthe reel-rotation restraining means is formed between the tooth edges ofthe reel gear. Therefore, even if the through hole is small, the toothedge of the driving gear which meshes the reel gear can reliably abutthe pushing-up portion of the releasing member projecting through thethrough hole and push the pushing-up portion. Since the movement of thereleasing member can be stably performed, the restraining member can bereliably released with a predetermined amount of movement, and theoperational reliability of the reel-rotation restraining means can beassured.

[0016] In addition, in another magnetic tape cartridge of the presentinvention, the reel is provided with a reel gear which meshes thedriving gear of the drive-side rotation drive means, and a pushing-upportion formed in part of the releasing member is provided so that adistal end thereof can abut the driving gear through a through holeprovided in the reel gear. The pushing-up portion and the through holeare brought into contact with each other through small protrusions whichreduce the contact area.

[0017] According to a magnetic tape cartridge such as theaforementioned, the pushing-up portion provided in the releasing memberof the reel-rotation restraining means, and the through hole provided inthe reel, are brought into contact with each other through smallprotrusions which reduce the contact area. As a result, the frictionresistance between the two is reduced, and even if bending deformationdevelops in the releasing member, movement of the pushing-up portionscan be stably performed according to the chucking operation of thedrive-side rotation drive means. In addition, the restraining member canbe reliably released with a predetermined amount of movement, andmovement to the restrained state can also be assured. Thus, theoperational reliability of the reel-rotation restraining means can beassured.

[0018] In a preferred form of the magnetic tape cartridge, the oppositetooth edges of the reel gear between which the through hole is bored areremoved so that they become flat shapes, curved surface shapes, orchambered surface shapes.

[0019] Another magnetic tape cartridge is characterized in that thereleasing member is formed by pressing of a metal sheet.

[0020] Still another magnetic tape cartridge is characterized in thatthe reel is provided with a guide member which guides part of thereleasing member in an inserting direction when inserting the pushing-upportion of the releasing member into the through hole.

[0021] A further magnetic tape cartridge is characterized in that thepushing-up portion of the releasing member is provided near each vertexof a generally triangular plate base. In a preferred form of thismagnetic tape cartridge, the plate base of the releasing member isformed integrally with the pushing-up portion with high-rigidity resinmaterial, while a sliding-contact portion, formed with a separate memberhaving a low friction characteristic, is rigidly attached integrally toa center portion of an upper surface of the base which comes intocontact with a center portion of a lower surface of the restrainingmember.

[0022] Another magnetic tape cartridge is characterized in that gatetraces for injection molding are provided near centers of rotation ofthe restraining member and the releasing member. In a preferred form ofthis magnetic tape cartridge, in the releasing member which has thepushing-up portion and is formed by injection molding, such a bore whichreduces a wall thickness of the pushing-up portion is formed in theinterior of the pushing-up portion.

[0023] Still another magnetic tape cartridge is characterized in thatthe reel gear is driven to rotate in mesh with a driving gear in which atooth edge portion thereof is formed into a curved surface.

[0024] A further magnetic tape cartridge is characterized in that atooth edge portion of the reel gear is formed into a curved surface.

[0025] Another magnetic tape cartridge is characterized in that the reelis formed by molding a metal reel plate on a bottom surface thereof byinsert molding, and the reel is molded by a metal mold in which a holdmember for holding an inner peripheral surface of the reel plate isdisposed on an outer periphery of a gate.

[0026] Still another magnetic tape cartridge is characterized in thatthe reel is formed by molding a metal reel plate on the inner peripheralside of the reel gear by insert molding, and the reel is molded by ametal mold provided with a means of preventing interference between agear-portion metal mold for molding the reel gear and the reel plate.

[0027] A further magnetic tape cartridge is characterized in that thereel is formed by molding a metal reel plate by insert molding and inthat the reel is formed so that outside the outer peripheral surface ofthe reel plate, a clearance in the form of a circumferential groove isformed between the outer peripheral surface and a bottom wall of thereel, and so that outside the clearance, the reel gear is formed.

[0028] Another magnetic tape cartridge is characterized in that the reelis formed by molding a metal reel plate by insert molding and in thatthe reel is formed so that a reinforcement rib is formed on a surface ofthe reel plate which contacts a bottom wall of the reel.

[0029] Still another magnetic tape cartridge is characterized in thatthe reel is formed by molding a metal reel plate by insert molding andin that the reel is formed so that a recess is formed in a bottom wallof the reel which the reel plate contacts.

[0030] A further magnetic tape cartridge is characterized in that thereel is formed by joining a reel hub and an upper flange portion byadhesion, and in that the reel is formed so that the upper flangeportion is provided with a collar portion which fits onto an innerperipheral surface of the reel hub, an annular protruding portion isformed between the collar portion and a surface of the upper flangeportion, and so that an end surface of the annular protruding portionand an outer peripheral surface of the collar portion are adhered to thereel hub as adhesion surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 is a front sectional view of a magnetic tape cartridge ofan embodiment of the present invention in the non-operative condition;

[0032]FIG. 2 is an exploded perspective view of the essential parts ofthe magnetic tape cartridge of FIG. 1;

[0033]FIG. 3 is a sectional view of the essential parts of the magnetictape cartridge of FIG. 1 in the operative condition;

[0034]FIG. 4 is a vertical sectional view of the essential parts of thethrough hole of the reel and the pushing-up portion of the releasingmember in FIG. 1;

[0035]FIG. 5A is a sectional view showing the essential parts of anotherembodiment of the pushing-up portion of the releasing member before achucking operation;

[0036]FIG. 5B is a sectional view showing the essential parts of FIG. 5after the chucking operation;

[0037]FIG. 6 is a sectional view showing the essential part of anotherembodiment of the reel gear;

[0038]FIG. 7 is a perspective view showing another embodiment of thereleasing member;

[0039]FIG. 8 is a perspective view showing still another embodiment ofthe releasing member;

[0040]FIG. 9A is a cross sectional view showing another embodiment ofthe through hole of the reel and the pushing-up portion of the releasingmember;

[0041]FIG. 9B is a cross sectional view showing still another embodimentof the through hole of the reel and the pushing-up portion of thereleasing member;

[0042]FIG. 10A is a cross sectional view showing a further embodiment ofthe through hole of the reel and the pushing-up portion of the releasingmember;

[0043]FIG. 10B is a cross sectional view showing a further embodiment ofthe through hole of the reel and the pushing-up portion of the releasingmember;

[0044]FIG. 11 is a front sectional view of a magnetic tape cartridge ofanother embodiment in the non-operative condition;

[0045]FIG. 12 is an exploded perspective view of the essential parts ofthe magnetic tape cartridge of FIG. 11;

[0046]FIG. 13 is a sectional view of the essential parts of the magnetictape cartridge of FIG. 11 in the operative condition;

[0047]FIG. 14 is a sectional plan view showing the assembled state ofthe reel and releasing member of FIG. 11;

[0048]FIG. 15 is an enlarged part-plan view of the reel of FIG. 11;

[0049]FIG. 16 is a sectional view of the essential parts of the reel andreleasing member of FIG. 11;

[0050]FIG. 17 is a front sectional view of a magnetic tape cartridge ofstill another embodiment in the non-operative condition;

[0051]FIG. 18 is an exploded perspective view of the essential parts ofthe magnetic tape cartridge of FIG. 17;

[0052]FIG. 19 is a sectional view of the essential parts of the magnetictape cartridge of FIG. 17 in the operative condition;

[0053]FIG. 20 is a plan view of the essential parts cut between theupper surface of the releasing member and the lower surface of therestraining member in FIG. 19;

[0054]FIG. 21 is an enlarged sectional view of the center portion of thereleasing member;

[0055]FIG. 22 is an enlarged sectional view of the center portion of thereleasing member in another embodiment;

[0056]FIG. 23 is a front sectional view of a magnetic tape cartridge ofa further embodiment in the non-operative condition;

[0057]FIG. 24 is an exploded perspective view of the essential parts ofthe magnetic tape cartridge of FIG. 23;

[0058]FIG. 25 is a sectional view of the essential parts of the magnetictape cartridge of FIG. 23 in the operative condition;

[0059]FIG. 26A is a sectional view showing an injection-molded state ofthe restraining member;

[0060]FIG. 26B is an enlarged view of the portion A in FIG. 26A;

[0061]FIG. 27A is a sectional view showing an injection-molded state ofthe releasing member;

[0062]FIG. 27B is an enlarged view of the portion B in FIG. 27A;

[0063]FIG. 28 is a sectional view showing another injection-molded stateof the releasing member;

[0064]FIG. 29 is a front sectional view of a magnetic tape cartridge ofa further embodiment in the non-operative condition;

[0065]FIG. 30 is an exploded perspective view of the essential parts ofthe magnetic tape cartridge of FIG. 29;

[0066]FIG. 31 is a sectional view of the essential parts of the magnetictape cartridge of FIG. 29 in the operative condition;

[0067]FIG. 32 is a plan view of the essential parts cut between theupper surface of the releasing member and the lower surface of therestraining member in FIG. 31;

[0068]FIG. 33 is a side sectional view showing the essential parts of arigid attachment structure of the pushing-up portion of the releasingmember;

[0069]FIG. 34A is a side sectional view showing the essential parts ofanother rigid attachment structure of the pushing-up portion of thereleasing member;

[0070]FIG. 34B is a side sectional view showing the essential parts ofstill another rigid attachment structure of the pushing-up portion ofthe releasing member;

[0071]FIG. 35 is a sectional view showing the lower end portion of thepushing-up portion of a releasing member in another embodiment;

[0072]FIG. 36 is a plan view of the essential part of a driving gear;

[0073]FIG. 37A is a perspective view showing an example of the toothedge shape of FIG. 36;

[0074]FIG. 37B is a perspective view showing another example of thetooth edge shape of FIG. 36;

[0075]FIG. 38 is a bottom view of the essential portion of a reel gear;

[0076]FIG. 39 is a front sectional view of the essential portion of thereel gear;

[0077]FIG. 40A is a bottom view of the essential part of a reel inanother embodiment;

[0078]FIG. 40B is a sectional view of the injection-molded state of thereel shown in FIG. 40A;

[0079]FIG. 41A is a bottom view of the essential part of a reel in stillanother embodiment;

[0080]FIG. 41B is a sectional view of the injection-molded state of thereel shown in FIG. 41A;

[0081]FIG. 42 is a sectional view of an injection-molded state showinganother embodiment of the structure for locking a reel plate;

[0082]FIG. 43 is a sectional view of an injection-molded state showingstill another embodiment of the structure for locking a reel plate;

[0083]FIG. 44A is a front view showing another embodiment of the reelplate;

[0084]FIG. 44B is a sectional view of FIG. 44A;

[0085]FIG. 44C is another sectional view of FIG. 44A;

[0086]FIG. 45A is a front view showing still another embodiment of thereel plate;

[0087]FIG. 45B is a sectional view of FIG. 45A;

[0088]FIG. 46A is a front view showing another embodiment of the reelplate;

[0089]FIG. 46B is a sectional view of FIG. 46A;

[0090]FIG. 47A is a front view showing still another embodiment of thereel plate;

[0091]FIG. 47B is a sectional view of FIG. 47A;

[0092]FIG. 48A is a front view showing another embodiment of the reelplate;

[0093]FIG. 48B is a sectional view of FIG. 48A;

[0094]FIG. 49 is a sectional view showing another form of the reel plateand the reel gear;

[0095]FIG. 50 is a sectional view showing still another form of the reelplate and the reel gear;

[0096]FIG. 51 is a sectional view showing a further form of the reelplate and the reel gear;

[0097]FIG. 52 is a sectional view showing a further form of the reelplate and the reel gear;

[0098]FIG. 53A is a bottom view of the essential part of a reel inanother embodiment;

[0099]FIG. 53B is a sectional view of the injection-molded state of thereel shown in FIG. 53A;

[0100]FIG. 54 is a plan view showing another embodiment of the reelplate;

[0101]FIG. 55 is a plan view showing another embodiment of the reel;

[0102]FIG. 56 is a sectional view of a reel according to still anotherembodiment;

[0103]FIG. 57 is an enlarged view of the essential part of the reel ofFIG. 56; and

[0104]FIG. 58 is a sectional view of a reel according to a furtherembodiment; and

[0105]FIG. 59 is an enlarged view of the essential part of the reel ofFIG. 58.

BEST MODE FOR CARRYING OUT THE INVENTION

[0106] The present invention will hereinafter be described in detail,based on embodiments shown in the drawings. FIG. 1 is a sectional viewof a magnetic tape cartridge of an embodiment in the non-operativecondition, FIG. 2 an exploded perspective view of the essential parts,and FIG. 3 a sectional view of the essential parts in the operativecondition.

[0107] The magnetic cartridge 1 is constructed so that magnetic tape(not shown) is wound on a single reel 2 and that the reel 2 is housedrotatably within a cartridge case 3. The cartridge case 3 is formed byfastening an upper case 31 and a lower case 32, which is provided at acenter portion thereof with an opening 32 a, together with vis screws,etc. The magnetic tape cartridge 1 is also equipped with reel-rotationrestraining means 10 for allowing rotation of the reel 2 when beingused, and restricting the rotation when not being used.

[0108] The reel 2 consists of a bottomed cylindrical reel hub 21, inwhich magnetic tape is wound on the outer periphery, and upper and lowerflange portions 22 and 23 respectively projected in disk form in theradial direction from the upper and lower ends of the outer periphery ofthis reel hub 21. The reel hub 21 and the lower flange portion 22 areintegrally formed from synthetic resin and are united with the upperflange portion 23, for example, by ultrasonic welding. The reel hub 21is closed at a lower portion thereof by a bottom wall 21 a. A reel gear24, for driving the reel 2 to rotate, is provided in annular form in theradially outer portion of the lower surface of the bottom wall 21 a. Areal plate 25 for magnetic suction, formed from an annular metal plate,is attached on the radially inner side from this reel gear 24. And thereel gear 24 and reel plate 25 of the reel 2 are disposed to face anopening 32 a in the bottom surface of the cartridge case 3. Note thatthe reel 2 is urged downward by an urging member 5 to be describedlater.

[0109] In addition, driving-side rotation drive means 11 is equipped onthe upper end face of a rotating shaft 12 with a driving gear 13 and amagnet (not shown). With the chucking operation of the drive means 11,the magnetic tape cartridge 1 loaded into a bucket (not shown) on thedriving side is lowered to the rotating shaft 12. The driving gear 13meshes the reel gear 24, and the reel plate 25 is attracted by themagnet, whereby the meshed state is held.

[0110] Next, the mechanism of the reel-rotation restraining means 10will be described. This reel-rotation restraining means 10 has arestraining member 4 movable toward or away from the reel 2 in anup-and-down direction, the urging member 5 for urging the restrainingmember 4 in a restraining direction, and a releasing member 6 (syntheticresin molded product) for moving the restraining member in a releasingdirection.

[0111] 3 (three) through holes 26 penetrating the reel gear 24 in theup-and-down direction are disposed in the bottom wall 21 a of the reel 2at regular intervals on a circle. Furthermore, 3 (three) stopperprotrusions 27 are stood up in the upper surface of the bottom wall 21 aat regular intervals on a circle at positions different in phase fromthe through holes 26, the upper end of each stopper protrusion 27 beingformed into a gear tooth shape. Note that three or more through holes 26and three or more stopper protrusions 27 may be disposed, and the upperend of the stopper protrusion 27 may be formed into a plurality of gearteeth. In the reel 2 shown in FIG. 2, only the part of the bottom wall21 a cut away from the reel 2 is shown.

[0112] On the restraining member 4, a disc portion 41 thereof isdisposed within the reel hub 21 of the reel 2, facing the bottom wall 21a. A restraining gear 42 is formed in annular form in the radially outerportion of the lower surface of the disc portion 41 and is meshable withthe upper ends of the stopper protrusions 27. In addition, the centerportion of the lower surface of the disc portion 41 is projected into aconvex shape and contacts the center portion of the upper surface of thedisc portion 61 of the releasing member 6 that is to be described later.

[0113] Furthermore, a protruding portion 44 is formed on the uppersurface of the disc portion of the restraining member 4 so that itextends upward. This protruding portion 44 is provided with a stoppergroove 45 in the form of a cross, extending in the up-and-downdirection. On the other hand, a swivel stopping protrusion 33 which isinserted into the stopper groove 45 is stood up in the inner surface ofthe upper case 31 of the cartridge case 3. Also, with the engagementbetween the stopper groove 45 and the swivel stopping protrusion 33, therestraining member 4 is disposed so as to be movable in the up-and-downdirection without rotating. Note that the stopper groove 45 and theswivel stopping protrusion 33 may be provided in the form of a straightline. Also, the swivel stopping protrusion may be formed in therestraining member 4, and the stopper groove may be formed in the uppercase 31.

[0114] The urging member 5 such as a coil spring is compressedlyinterposed between the upper surface of the disc portion 41 on theradially outer side from the protruding portion 44 and the inner surfaceon the radially outer side of the swivel stopping protrusion 33, wherebythe restraining member 4 is urged downward in the restraining directionwhere the restraining gear 43 and the stopper protrusion 27 engage eachother.

[0115] In addition, the releasing member 6 is interposed between therestraining member 4 and the bottom wall 21 a of the reel hub 21 so thatit is movable up and down. At three positions on the radially outerportion of the disc portion 61 on the central side, arm portions 62 areformed to extend in the radial direction. The arm portions 62 areprovided on the outer lower surface with pushing-up portions 63 in theform of a square bar extending in the up-and-down direction,respectively. The pushing-up portions 63 are inserted into the throughholes 26 bored in the reel hub 21 so that they are movable into and outof the through holes 26, respectively. The lower ends of the pushing-upportions 63 are located facing the tooth portion of the reel gear 24 ofthe lower surface of the reel hub 21. At this time, each of the stopperprotrusions 27 is located between two adjacent arm portions 62. Notethat the pushing-up portion 63 may be formed into a round bar shape.

[0116] At the lower most position of the releasing member 6 (FIG. 1),the lower end face of the pushing portion 63 is at approximately thetooth edge position of the reel gear. As the driving gear 13 is meshedwith the reel gear 24 by the chucking operation of the drive-siderotation drive means 11, the releasing member 6 is pressed and is pushedup by a predetermined amount of stroke (FIG. 3). Also, if it is fittedinto the through holes 26 of the pushing-up portion 63, this releasingmember 6 rotates integrally with the reel 2. In addition, the lower endof the central convex portion of the lower surface of the restrainingmember 4 is urged to abut the upper surface of the releasing member 6 bythe urging member 5, and both make sliding contact with each other.

[0117] The through hole 26 formed in the reel gear 24 of the reel 2 isbored between adjacent tooth edges 24 a of the reel gear 24 so that ithas a width of one pitch, as shown in FIG. 4. That is, it is bored sothat the center of the pushing-up portion 63 of the releasing member 6inserted into this through hole 26 becomes the center of the toothgroove and coincides with the tooth edge of the driving gear 13 whichmeshes with this reel gear 24.

[0118] The opening width of the through hole 26 is provided so that itis about one pitch or two pitches of the real gear 24.

[0119] Note that at least either the restraining member 4 or thereleasing member 6 may be formed with synthetic resin containing alubricant such as molybdenum disulfide, polytetrafluoroethlene,graphite, potassium titanate whisker, silicon (various grades ofdimethylpolysiloxane and the degenerated substances), etc., whereby thelubrication may be improved. Also, along with the above-mentionedlubricant, a lubricant, such as, an oleic acid amide lubricant, anerucic acid lubricant, a stearic acid amide lubricant, a bisfatty acidamide lubricant, a non-ion interfacial active lubricant, a hydrocarbonlubricant, a fatty acid amide lubricant, an ester lubricant, an alcohollubricant, a metallic soap, etc., may be doped. Furthermore, it ispreferable that synthetic resin employ polycarbonate (PC),polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS) containingglass fiber, polyphenylenesulfide (PPS), aliphatic polyamide such asnylon 6 or nylon 66, aromatic polyamide, ultra high polymerpolyethylene, isotactic polypropylene, syndiotactic polystyrene; andwear-resisting resin with an imide group, such as polyimide,polyamideimide, polyetherimide, etc. This reduces the friction and wearbetween the sliding-contact portions of both, and because of a reductionin the driving resistance, the reel 2 can be stably rotated. Inaddition, the occurrence of powder due to wear is suppressed, wherebythe reliability of recording and reproducing performances can beassured.

[0120] The operation of the reel-rotation restraining means 10 will bedescribed. FIG. 1 shows a non-operative condition, such as an archivedcondition, etc., of the magnetic tape cartridge 1. In this condition,the restraining member 4, the releasing member 6, and the reel 2 aremoved to the side of the lower case 32 of the cartridge case 3 by theurging force of the urging member 5, and the opening 32 a of the centerportion of the lower case 32 is closed by the reel 2. The releasingmember 6 is in the lower most state in which the lower surface abuts theupper surface of the bottom wall 21 a of the reel hub 21, and thepushing-up portions 63 are projected so as to coincide with the toothedge position of the reel gear 24. The restraining member 4 abutting theupper surface of the releasing member 6 is also at its lowered position,and the upper end portions of the stopper protrusions 27 engage therestraining member 4, whereby rotation of the reel 2 when not being usedis restricted and forwarding of magnetic tape is inhibited.

[0121] On the other hand, when the cartridge of FIG. 3 in which themagnetic tape cartridge 1 is loaded into the drive is being used, therotating shaft 12 of the drive-side rotation drive means 11 approachesthe bottom surface of the reel 2, and with the chucking operation, thedriving gear 13 meshes the reel gear 24 and moves and holds the reel 2slightly upward. Then, the tooth edge of the driving gear 13 abuts thelower end of the pushing-up portion 63 of the releasing member 6 andpushes up this. As a result, the releasing member 6 moves upward againstthe urging force of the urging member 5, and the restraining member 4,along with this releasing member 6, also moves in the upward releasingdirection. This releases the engagement between the restraining gear 42and the stopper protrusions 27, whereby the reel 2 becomes free torotate. The magnetic tape is also forwarded or rewound by the drive of arecording-reproducing unit.

[0122] In the released state, the lower ends of the pushing-up portions63 of the releasing member 6 are abutted, within the through holes 26bored between the tooth edges of the reel gear 24, with the tooth edgesof the driving gear 13 with reliability and are pushed up, and theupward movement can be linearly performed with stability. Therefore, therestraining member 4 is moved by a predetermined amount of stroke,whereby the engagement between the restraining gear 42 and the stopperprotrusions 27 can be reliably released.

[0123] Next, FIGS. 5A and 5B show another embodiment, which is formed inthe same manner as the aforementioned embodiment, except that the lowerend of the pushing-up portion 63 of the releasing member 6 differs.

[0124] The pushing-up portion 63, as with the aforementioned, isinserted into the through hole 26 bored between the tooth edges 24 a ofthe reel gear 24, and a recess 63 a engageable with the tooth edge ofthe driving gear 13 is formed in the center portion of the lower endface of the pushing-up portion 63 which abuts the driving gear 13 of thedrive-side rotation drive means 11.

[0125] When the depth of mesh between the reel gear 24 and the drivinggear 13 is taken to be H and the depth of mesh between the restraininggear 41 and the stopper protrusion 27 (i.e., releasing height) is takento be D (not shown), the engagement depth h of the recess 63 a of thepushing-up portion 63 with the driving gear 13 is set so that theeffective pushing-up height (H−h) of the pushing-up portion 63 issufficiently greater than the releasing height (D), i.e., H−h>>D,whereby it is necessary to assure the releasing operation.

[0126] The pushing-up portion 63 in this embodiment has the recess 63 aat the lower end face. Therefore, with the chucking operation of thedrive-side rotation drive means 11, the tooth edge of the driving gear13 engages the recess 63 a of the pushing-up portion 63 from thenon-operative condition of FIG. 5A, as shown in FIG. 5A, and therefore,the reliable operation of pushing up the releasing member 6 is obtainedfrom the initial stage of the upward movement of the driving gear 13.

[0127]FIG. 6 illustrates another embodiment of the reel gear 24. Thelower ends of the opposite tooth edges 24 a of the reel gear 24 betweenwhich the through hole 26 is bored are removed so that they become flatshapes. The lower ends of the opposite tooth edges 24 a may be removedso that they become R shapes which form curved faces, or C shapes whichform chamfered faces, instead of becoming flat shapes.

[0128] The tooth edge 24 a of the rear gear 24 at the open end of thethrough hole 26 is sharp if it is left as it is, but since it is removedso as to be low in height, as described above, formation of the metalmold becomes easy and formability is enhanced.

[0129] Next, FIGS. 7 and 8 show other embodiments of the aforementionedreleasing member 6, in which releasing members 6 are formed by metalsheet pressing.

[0130] That is, in FIG. 7 a metal plate is punched out into thedevelopment shape of the disk portion 61, arm portions 62, andpushing-up portions 63 of the releasing member 6. The pushing-upportions 63 are formed by bending the outer extension portions of thearm portions 62 downward, and furthermore, abutting portions 63 b areformed by bending the lower end portions of the pushing-up portions 63inward. Note that the abutting portions 63 b may be formed in the sheetthickness of the pushing-up portion 63 without being bent.

[0131] Also, in the example of FIG. 8 the pushing-up portion 63 is bentdownward from the side portion of the outer end of the arm portion 62,and furthermore, the abutting portion 63 b is formed by bending thelower end portion of the pushing-up portion 63.

[0132] For the aforementioned releasing members 6 that are formed bymetal sheet pressing, it becomes easy to assure rigidity and it ispossible to design them to a thickness such that the releasing membercannot obtain sufficient rigidity when formed from synthetic resin.Therefore, thinning of the releasing member 6 makes it easy to assurethe installation space for the reel-rotation restraining means 10, and areduction in the size of the through hole 26 in the reel gear 24 canincrease the area of mesh of the reel 2 with the drive-side rotationdrive means 11.

[0133] Next, FIGS. 9A and 9B show other embodiments of the through hole26 and pushing-up portion 63. The inner periphery of the through hole 26formed in the reel gear 24 of the reel 2 and the outer periphery of thepushing-up portion 63 of the releasing member 6 are constructed so thatthey contact each other through small protrusions, provided on eithersurface, which reduce the contact area.

[0134] First, in the example of FIG. 9A, the pushing-up portion 63 issquare in cross section and the surface is smooth, and small protrusions26 a are formed on the inner periphery of the through hole 26 in thelongitudinal direction along the moving direction of the pushing-upportion 63. In the example of FIG. 9B, the through hole 26 is square incross section and the inner surface is smooth, and small protrusions 63d are formed on the surface of a pushing-up portion 63 in the form of asquare bar, in the longitudinal direction along the moving direction.The above-mentioned small protrusions 26 a, 63 d are about a few tens μmin height, and in the drawings, they are shown on an enlarged scale.

[0135] In FIGS. 10A and 10B there is shown a further embodiment in whichthe pushing-up portion 63 is formed into a round bar shape, and smallprotrusions which reduce a contact area are provided on the innerperiphery of a through hole 26 formed in the shape of a square hole.

[0136] That is, in the example of FIG. 10A, the surface of thepushing-up portion 63 in the form of a round bar is smooth, and aplurality of small protrusions 26 a are formed on each surface of theinner surfaces of the through hole 26 in the longitudinal directionalong the moving direction of the pushing-up portion 63. In the exampleof FIG. 10B, the surface of the pushing-up portion 63 in the form of around bar is smooth, and a small protrusion 26 a is formed in the centerportion of each surface of the inner surfaces of the through hole 26 inthe longitudinal direction along the moving direction of the pushing-upportion 63. Note that small protrusions which reduce a contact area maybe provided on the surface of the pushing-up portion 63 in the form of around bar. In addition, the through hole 26 may be formed into the shapeof a round hole.

[0137] In the movement of the reel-rotation restraining means 10 in thisexample from the restrained state to the released state, or the movementfrom the released state to the restrained state, the outer periphery ofthe pushing-up portion 63 of the releasing member 6 and the innerperiphery of the through hole 26 of the reel 2 are in contact with eachother through small protrusions 26 a or 26 b which reduce the contactarea, and therefore, the frictional resistance becomes smaller andstable movement of the pushing-up portion 63 is reliably performed.

[0138] Next, FIG. 11 is a sectional view of a magnetic tape cartridge ofanother embodiment in the non-operative condition, FIG. 12 an explodedperspective view of the essential parts, and FIG. 13 a sectional view ofthe essential parts in the operative condition.

[0139] The basic structure and operation of a reel 2, a cartridge case3, reel-rotation restraining means 10, etc., of a magnetic tapecartridge 1 in this embodiment are the same as the aforementionedembodiment, and the same reference numerals will be applied to the sameparts to omit a description thereof.

[0140] Note that three pairs of two stopper protrusions 27 are stood upin the upper surface of the bottom wall 21 a of the reel 2 at regularintervals on a circle at positions different in phase from through holes26, the upper end of each stopper protrusion 27 being formed into aplurality of gear teeth. Note that three or more through holes 26 andthree or more stopper protrusions 27 may be disposed, and the upper endof the stopper protrusion 27 may be formed into a single gear tooth. Inthe reel 2 shown in FIG. 2, only the part of the bottom wall 21 a cutaway from the reel 2 is shown.

[0141] In addition, the releasing member 6 of the reel-rotationrestraining means 10 is provided on the lower surfaces near the vertexesof a generally triangular plate base 61 with pushing-up portions 63 inthe form of a column extending in the up-and-down direction,respectively. Between the pushing-up portions 63, the stopperprotrusions 27 are positioned outside the plate base 61. Note that thepushing-up portion 63 may be formed into the shape of a square pillar,an elliptic cylinder, etc.

[0142] Also, in the reel 2, guide members 28 are installed for guidingpart of the releasing member 6 in an inserting direction when thepushing-up portions 63 of the releasing member 6 are inserted into thethrough holes 26. The guide members 28, as shown in FIGS. 16 through 18,are formed with two guide ribs, extending in the up-and-down direction(direction of inserting the pushing-up portion 63), which guide bothcorner portions of each vertex of the generally triangular plate base 61of the releasing member 6 to the inner wall of the reel hub 21 of thereel 2 near the through hole 26 formed in the reel gear 24.

[0143] The height H1 (refer to FIG. 16) of the guide member 28 (guiderib) is formed greater than the height h1 of the pushing-up portion 63so that when the pushing-up portion 63 is inserted into the through hole26 downward, the plate base 61 is guided before the lower end portion ofthe pushing-up portion 63 reaches the upper open end of the through hole26. In addition, the circumferential edge of the upper open end of thethrough hole 26 is formed into a taper face 26 b so that the lower endof the pushing-up portion 63 is guided into the through hole 26.

[0144] If holding of the releasing member 6 is released and drops aftereach vertex of the plate base 61 is positioned by the guide member 28 sothat each pushing-up portion 63 of the releasing member 6 is above eachthrough hole 26, the pushing-up portion 63 is moved in the insertingdirection and inserted into the through hole 26 by the guide of theguide member 28 in the inserting direction, whereby the releasing member6 is assembled into the reel 2.

[0145] Note that for assembling of the magnetic tape cartridge 1, thelower case 32 is placed facing upward, and the reel 2 is placed on this.Subsequently, the releasing member 6 is installed while being guided bythe guide members 28, and the restraining member 4 and the urging member5 are placed on the member 6. Then, the upper case 31 is placed, andthereafter, the top and bottom are reversed and screws are tightenedthrough the side of the lower case 32, whereby assembling is completed.

[0146] While, in this embodiment, the guide members 28 are formed in theinner wall of the reel hub 21, the installation position is not limitedto this. At positions where the guide members 28 do not interfere withthe restraining member 4, the guide members 28 may be projected from thebottom wall 21 a of the reel 2 so that part of the releasing member 6 isguided in the inserting direction of the pushing-up portion 63. Inaddition, the through holes 26 may be provided in the radially innerside from the reel gear 24.

[0147] According to this embodiment, the positioning of the pushing-upportions 63 in inserting the pushing-up portions 63 of the releasingmember 6 into the through holes, and the assembling of the reel 2 andthe releasing member 6 through guiding of the movement in the insertingdirection, can be easily performed by providing the guide members 28 inthe reel 2. As a result, assembling of the magnetic tape cartridge 1 asa whole can be efficiently performed.

[0148] Particularly, if the pushing-up portions 63 of the releasingmember 6 are inserted into the through holes 26 bored in the reel gear24 provided in the reel 2 and the lower ends of the pushing-up portions63 can abut the driving gear 13, and if the guide members 28 (guideribs) extending in the inserting direction of the pushing-up portion 63are provided in the inner wall of the reel 2 near the through holes 26,the guide members 28 can be formed without interfering with othercomponents such as the restraining member 4, etc., and guiding of thereleasing member 6 at the time of assembling can be satisfactorilyperformed near the through holes 26.

[0149] Next, FIG. 17 is a sectional view of a magnetic tape cartridge ofstill another embodiment in the non-operative condition, FIG. 18 is anexploded perspective view of the essential parts, FIG. 19 is a sectionalview of the essential parts in the operative condition, and FIG. 20 is aplan view of a releasing member in the assembled state.

[0150] The basic structure and operation of a reel 2, a cartridge case3, reel-rotation restraining means 10, etc., of a magnetic tapecartridge 1 in this embodiment are the same as the aforementionedembodiment, and the same reference numerals will be applied to the sameparts to omit a description thereof.

[0151] The releasing member 6 of the reel-rotation restraining means 10is provided on the lower surfaces near the vertexes of a generallytriangular plate base 61 with pushing-up portions 63 (leg portions) inthe form of a column extending in the up-and-down direction,respectively. The base 61 is formed integrally with the pushing-upportions 63 by high-rigidity resin material, while at the center portionof the upper surface a sliding-contact portion 64 which contacts thecenter portion of the lower surface of the restraining member 4 isformed with a separate member having a low friction characteristic andis rigidly attached integrally to the base 61. The center portion of thelower surface of the disc portion 41 of the restraining member 4 isformed into a convex shape and is pushed against the sliding-contactportion 64.

[0152] The sliding-contact portion 64, as shown in FIG. 21, is providedby a resin molded product in the form of a disk block and is rigidlyattached within the recess of the base 61, with the upper surfaceprojected from the upper surface of the base 61.

[0153] As high-rigidity resins for forming the base 61 of the releasingmember 6, there are, for example, polycarbonate (PC) or PC doped withglass fiber, ABS resin doped with glass fiber, etc. Also, aslow-friction characteristic materials for the sliding-contact portion64, there are polyoxymethylene (POM), nylon dopped with molybdenumdisulfide, polytetrafluoroethylene (PTFE), etc.

[0154]FIG. 22 illustrates another embodiment of the sliding-contactportion 64 of the releasing member 6. This sliding-contact portion 64 isformed by fixedly attaching a separate member, formed into a tape-likeshape, which has a low friction characteristic, at a flat centerposition of the base 6.

[0155] Also, in the released state in the reel-rotation restrainingmeans 10, the pushing-up portions 63 of the lower ends of the releasingmember 6 are pushed upward by the driving gear 13, while the urgingforce of the urging member 5 acts downward through the restrainingmember 4 and therefore bending deformation will easily develop in thebase 61. However, since this base 61 is molded with high-rigidity resin,the bending deformation becomes smaller. Therefore, the pushing-upportion 63 can move linearly into and out of the through hole 26 withstability without contacting one side of the through hole 26, and theengagement of the restraining gear 41 and the stopper protrusions 27 canbe reliably released by moving the restraining member 4 by apredetermined amount of stroke. In addition, because the thickness ofthe releasing member 6 can be reduced, an amount of stroke for movementcan be sufficiently assured.

[0156] On the other hand, if the reel 2 is rotated by forwarding orrewinding the magnetic tape with the drive unit of therecording-reproducing unit, the releasing member 6 rotates integrallywith the reel 2, but the restraining member 4 does not rotate because itis in a state locked integrally to the side of the cartridge case 3. Thereleasing member 6 rotates and slides in a low friction or low wornstate with respect to the restraining member 4 through thesliding-contact portion 64 having a low friction characteristic. Thisreduces the rotation resistance of the reel 2 and enhances thewear-resisting property, whereby the occurrence of powder due to wearcan also be reduced.

[0157] According to this embodiment such as the aforementioned, the base61 of the releasing member 6 is molded with high-rigidity resinmaterial, and the sliding-contact portion 64 contacting the restrainingmember 4 is formed with a separate member having a low frictioncharacteristic. Therefore, the rigidity of the releasing member 6 isenhanced and the bending deformation is reduced. Since stable movementof the releasing member 6 is performed, the restraining member 4 can bereliably released with a predetermined amount of movement, and theoperational reliability of the reel-rotation restraining means 10 can beassured. In addition, the friction and wear between the sliding-contactportions of both are reduced, and because of a reduction in theresistance to driving, stable rotation of the reel 2 can be performed.The occurrence of powder due to wear is reduced, whereby the reliabilityin recording-reproducing performance can be assured. Thus, the releasingmember 6 is also suitable for mass production.

[0158] That is, the releasing member 6 requires high rigidity and a lowfriction characteristic. However, if it is provided by an integral resinmolded product, there is no resin material meeting both requirements,and even if it did exist, it would be a special and expensive materialand will not be suitable for mass production.

[0159] Next, FIG. 23 is a sectional view of a magnetic tape cartridge ofa further embodiment in the non-operative condition, FIG. 24 is anexploded perspective view of the essential parts, and FIG. 25 is asectional view of the essential parts in the operative condition.

[0160] The basic structure and operation of a reel 2, a cartridge case3, reel-rotation restraining means 10, etc., of a magnetic tapecartridge 1 in this embodiment are the same as the aforementionedembodiment, and the same reference numerals will be applied to the sameparts to omit a description thereof.

[0161]FIG. 26A is a diagram showing how the restraining member 4 of thereel-rotation restraining means 10 is molded by injection molding, andFIG. 26B is an enlarged view of the essential part A in FIG. 26A. Therestraining member 4 is molded by injecting resin into a space formed bya stationary metal mold 71 and a movable metal mold 72 through a gatefrom a runner 73. At this time, the runner 73 is connected to aprotruding portion 43, formed at the rotation center position of thereel 2 on the opposite surface of the restraining member 4 from thesurface which slides on the releasing member 6, and when the movablemetal mold 72 is moved in order to take out a molded product aftermolding, the runner 73 is separated from the restraining member 4 and agate trace 46 is formed.

[0162]FIG. 27A is a diagram showing how the releasing member 6 is moldedby injection molding, and FIG. 27B is an enlarged view of the essentialpart B in FIG. 27A. The releasing member 6 is molded by injecting resininto a space formed by a stationary metal mold 74 and a movable metalmold 75 through a gate from a runner 76. At this time, the runner 76 isconnected at the rotation center position of the reel 2 to the oppositesurface of the releasing member 6 from the surface which slides on therestraining member 4, and when the movable metal mold 75 is moved inorder to take out a molded product after molding, the runner 76 isseparated from the releasing member 6 and a gate trace 67 is formed.

[0163] Thus, by providing the gate traces 46 and 67, for injectionmolding, on the sliding surfaces of the restraining member 4 and thereleasing member 6 in the vicinity of the center of rotation of the reel2, there is no possibility that when the restraining member 4 and thereleasing member 6 slide on each other, the sliding resistance betweenthe restraining member 4 and the releasing member 6 will increase andpowder due to wear will occur. In addition, because the gate traces 46and 67 are provided in the vicinity of the rotation center, the flow ofresin within the metal molds 71, 72, 74, and 75 becomes approximatelyuniform. With this uniformity, there is no possibility that thedimensional precision of the restraining member 4 and releasing member 6will be deteriorated, and in addition, the restraining member 4 and thereleasing member 6 can be manufactured satisfactorily in terms ofappearance and strength.

[0164] Note that while, in the above-mentioned embodiment, the gatetraces 46 and 67 are provided at the rotation center positions of thereel 2 on the restraining member 4 and the releasing member 6, there isno problem even if they are shifted slightly from the rotation centerpositions, if they are formed on the surfaces of the restraining member4 and the releasing member 6 opposite to the sliding surfaces of themembers 4, 6.

[0165] In addition, although, in the above-mentioned embodiment, in bothof the restraining member 4 and the releasing member 6 the gate traces46 and 67 are formed on the surfaces of the members 4 and 6 oppositefrom the sliding surfaces thereof, the gate trace may be formed on thesurface of either the restraining member 4 or the releasing member 6opposite to the sliding surface.

[0166] Furthermore, in the above-mentioned embodiment, while thereleasing member 6 is injection-molded as shown in FIG. 27A, thepushing-up portions 63 of the releasing member 6 need to be stood up ina direction perpendicular to the plate base 61, because they areinserted into the through holes 26 and moved. However, there is apossibility that the pushing-up portions 61 cannot be precisely formed,because the plate base 61 will warp due to sinkmarks in the resin whichare formed when molding the releasing member 6 by injection molding. Inaddition, as the gate trace 67 and the three pushing-up portions 63 areformed on the side of the stationary metal mold 74, as shown in FIG.27A, there is a problem that (1) the sliding resistance between thereleasing member 6 and the stationary metal mold 74 will become greater,(2) the releasing member 6 will be pulled toward the side of thestationary metal meld 74 when the stationary metal mold 74 and themovable metal mold 75 are opened, and (3) a molded product cannot betaken out smoothly from the metal molds 74 and 75.

[0167] Because of this, it is preferable to form a bore 6 a to such anextent that it will reduce the wall thickness of the pushing-up portion63, at a position, corresponding to the pushing-up portion 63, on theside opposite to the movable metal mold 75 of the releasing member 6.That is, a pin-shaped protruding portion 75 a is formed at a position onthe movable metal mold 75 which corresponds to the pushing-up portion63, and the bore 6 a is formed in the releasing member 6 when moldingthe releasing member 6 by injection molding. Since the position on thereleasing member 6 corresponding to the pushing-up portion 63 is awayfrom the gate, there is significant shrinkage when the resin hardens.Therefore, when the releasing member 6 hardens within the metal molds 74and 75, the bore 6 a shrinks and the holding force of the protrudingportion 75 a of the movable metal mold 75 develops. This prevents thereleasing member 6 from being pulled by the stationary metal mold 74when releasing the metal molds 74 and 75, making it possible to smoothlyrelease the metal molds 74 and 75 and accordingly take-out a moldedproduct.

[0168] In addition, sinkmarks in the resin can be prevented by makingthe wall thickness of the pushing-up portion 63 uniform. This canprevent the fall of the pushing-up portions 63 during molding. As aresult, the dimensional precision of the pushing-up portion 63 can beenhanced.

[0169] According to this embodiment as described above, the gate traces67 and 46 for injection molding are provided near the centers ofrotation of the reel 2 on the surfaces of the restraining member 4 andthe releasing member 6 opposite from the sliding surfaces thereof.Therefore, there is no possibility that with irregularities on the gatetraces, the sliding resistance between the restraining member 4 and thereleasing member 6 will increase and powder due to wear will occur. Inaddition, because the gate traces 46 and 67 are provided in the vicinityof the rotation center of the reel 2, the flow of resin within the metalmolds 71, 72, 74, and 75 becomes approximately uniform. This uniformflow prevents the deterioration of the dimensional precision of therestraining member 4 and releasing member 6 and also makes it possibleto manufacture the restraining member 4 and the releasing member 6satisfactorily from the point of view in appearance and strength.

[0170] Next, FIG. 29 is a sectional view of a magnetic tape cartridge ofa further embodiment in the non-operative condition, FIG. 30 an explodedperspective view of the essential parts, FIG. 31 a sectional view of theessential parts in the operative condition, and FIG. 32 a plan view of areleasing member in the assembled state.

[0171] The basic structure and operation of a reel 2, a cartridge case3, reel-rotation restraining means 10, etc., of a magnetic tapecartridge 1 in this embodiment are the same as the aforementionedembodiment, and the same reference numerals will be applied to the sameparts to omit a description thereof.

[0172] The releasing member 6 of the reel-rotation restraining means 10is provided on the lower surfaces near the vertices of a generallytriangular metal plate base 61 with pushing-up portions 63 (legportions) in the form of a column extending in the up-and-downdirection, respectively.

[0173] The pushing-up portion 63 is formed with a metal processedproduct or a resin molded product, and as shown in FIG. 33, the cornerportions of the lower end are chamfered so that no edges are formed. Theupper end portion of this pushing-up portion 63 is provided with anattaching portion 63 f that consists of a bar-shaped screw. Theattaching portion 63 f is screwed into a screw hole 61 a formed in eachvertex portion of the base 61 and is rigidly attached.

[0174] In addition, FIGS. 34A and 34B show other embodiments of therigid structure for attaching the pushing-up portion 63 of the releasingmember 63 to the base 61. In FIG. 34A, a snap-type attaching portion 63g is formed integrally in the upper end portion of a resin pushing-upportion 63, and the attaching portion 63 g is inserted into a steppedattaching hole 61 b formed in each vertex portion of the base 61 and isrigidly attached. In FIG. 34B, a metal clip-type attaching portion 63 his formed integrally in the upper end portion of the resin pushing-upportion 63, and the attaching portion 63 h is inserted into a attachinghole 61 c formed in each vertex portion of the base 61 and is rigidlyattached.

[0175] Besides, the rigid attachment of the pushing-up portion 63 to thebase 61 can adopt known methods such as press-fit, caulking (heat,welding), shrinkage fit, etc. It is preferable that for the attachingportions 63 f to 63 h in the pushing-up portions 63, the attachingportion in the metal pushing-up portion be formed by cutting, or byrigidly attaching a separate component. It is also preferable that forthe resin pushing-up portion, the resin attaching portion be providedintegrally by molding, or rigidly attached by welding, etc., or themetal attaching portion be provided by insert molding.

[0176] Next, FIG. 35 shows that in the case of the resin pushing-upportion 63, metal material 63 k is rigidly attached to a surface of thelower end portion of the pushing-up portion 63 which contacts thedriving gear 13. In this embodiment, the wear-resisting property of theresin pushing-up portion 63, which is contacted by the driving gear 13made of metal, is enhanced. The metal material 63 k is provided byattachment of a metal plate (metal foil), insert molding, etc.

[0177] In the released state in the reel-rotation restraining means 10,the pushing-up portions 63 of the lower ends of the releasing member 6are pushed upward by the driving gear 13, while the urging force of theurging member 5 acts downward through the restraining member 4 andtherefore bending deformation will easily develop in the base 61.However, since this base 61 is formed from metal, bending deformationbecomes smaller. The pushing-up portion 63 can also be preciselyattached by a separate member. Therefore, the pushing-up portion 63 canlinearly move into and out of the through hole 26 with stability withoutcontacting one side of the through hole 26, and the engagement of therestraining gear 41 and the stopper protrusions 27 can be reliablyreleased by moving the restraining member 4 by a predetermined amount ofstroke. In addition, because the thickness of the releasing member 6 canbe reduced, an amount of stroke for movement can be sufficientlyassured. Furthermore, the driving gear 13 is capable of smoothlyabutting the pushing-up portion 63, and there is no possibility that thedriving gear 13 will be caught on the edge portion.

[0178] Note that if the driving gear 13 is made of metal and the toothedge is sharp, it will wear the pushing-up portion 63 when it abuts thepushing-up portion 63, and therefore, the driving gear 13 made of metalwill be disadvantageous in terms of durability. Because of this, it ispreferable to form the tooth edge of the driving gear 13 into a curvedsurface, as shown in FIGS. 36, 37A, and 37B.

[0179] In FIGS. 36, 37A, and 37B, the tooth edge portion 13 a of thedriving gear 13, as a shape of facilitating metal cutting of the drivinggear 13, is formed so that the edge is flat at the radially outerportion and sharp and low in height at the radially inner portion, theangles of the tooth side faces differ at both sides, and the toothgroove 13 b is formed wide. In the form shown in FIG. 37A, the edge ofthe tooth edge portion 13 a on the radially inner side which becomessharp is formed into a curved surface (R-surface) by chamfering, wherebydamage to the reel gear 24 which meshes with this driving gear 13 anddamage to the lower end of the pushing-up portion 63 of the releasingmember 6, which will occur when they abut each other, are alleviated.Similarly, in the form of FIG. 37B, the radially outer flat edge of thetooth edge portion 13 a, as with the radially inner side, is formed intoa curved surface (R-surface) by chamfering.

[0180] Furthermore, in the case where the reel gear 24 formed in thereel 2 has the same gear shape as the driving gear 13, the tooth edgemay likewise be formed into a curved surface (R-surface) by chamfering.

[0181]FIGS. 38 and 39 show a gear shape example of the reel gear 24. Thetop of the tooth edge portion 24 a is formed into a flat surface at theradially inner and outer portions so that a sharp edge portion is notformed. The angles of the tooth side faces of this reel gear 24 differat both sides, the tooth groove 24 b is formed wide and deep, and theflat face of the tooth edge portion 24 b is formed so that the radiallyinner and outer widths are approximately the same. This can increase thestrength of the reel gear 24 made of resin and prevent the tooth frombreaking when it meshes the driving gear 13 made of metal. Note that thedriving gear 13 may likewise be formed so that the top of the tooth edgeportion is flat.

[0182] According to this embodiment such as the aforementioned, the base61 of the releasing member 6 is made of metal, while the pushing-upportion 63 is formed as a separate body and rigidly attached to the base91. Therefore, the releasing member 6 is enhanced in dimensionalprecision and rigidity, and the bending deformation is reduced. Thesliding motion of the pushing-up portion 63 within the through hole 26can also be assured. Since stable movement of the releasing member 6 canbe performed, the restraining member 4 can be reliably released with apredetermined amount of movement, and the operational reliability of thereel-rotation restraining means 10 can be assured.

[0183] In addition, if at least the lower end portion of the pushing-upportion 63 is made of metal, the durability to the pressing action onthe lower end of this pushing-up portion is enhanced.

[0184] Next, an embodiment related to the reel and the manufacturingmethod will be described. FIG. 40A shows a bottom view of the reel plate25 (metal plate) of the bottom center of the reel 2, and FIG. 40B showsa sectional view of the molded state.

[0185] The reel plate 25 is formed into an annular shape having a centerhole 25 a. In the molded state with the reel plate 25 inserted into thebottom wall 21 a of the reel 2, the part of the center hole 25 a isclosed by the resin of the bottom wall 21 a, and so as the reel gear 24is provided to project from the-plate surface.

[0186] Injection molding of the reel 2, as shown in FIG. 40B, isperformed by injecting resin into a cavity formed by a stationary metalmold 71 and a movable metal mold 72 through the gate 77 a of a gate bush77. The gate bush 77 is disposed in the center portion of the stationarymetal mold 71, and a hold member 78 to hold the inner peripheral surfaceof the reel plate 25 is disposed on the outer periphery of the gate bush77. The hold member 78 is tubular in cross section and provided at thelower end with a ring protrusion 78 a. The inner peripheral surface ofthe center hole 25 a of the reel plate 25 is fitted onto the outerperipheral surface of the ring protrusion 78 a. This reel plate 25 isheld with the plate surface being in intimate contact with an innersurface which is at a predetermined position on the metal mold 71. Inthis manner, the movable metal mold 72 is closed, and resin is injected.

[0187] After molding, the hold trace 21 b of the ring protrusion 78 a ofthe hold member 78 is formed as a ring groove in the reel 2, at the partof the bottom wall 21 a closing the center hole 25 a of the reel plate25. In addition, a gate trace 21 c is formed in the center portion.

[0188] If insert molding is performed with the inner peripheral surfaceof the center hole 25 a of the reel plate 25 held by the above-mentionedhold member 78, the reel plate 25 can be prevented from moving andshifting out of position because of the flow of resin, and therefore,the reel plate 25 can be rigidly attached at a predetermined position onthe reel 2. In addition, all that is required at the time of wear is tochange components, because the hold member 78 is formed as a memberseparate from the stationary metal mold 71 and the gate bush 77.

[0189]FIG. 41A shows another embodiment of the structure for holding thereel plate 25 and FIG. 41B the molded state. In this example, the lowerend of the hold member 78 for holding the reel plate, provided in thestationary metal mold 71, has a pin structure.

[0190] That is, the hold member 78 is tubular in cross section, andthree or more hold pins 78 b (in the figure, 3 pins) project from thelower end. The outer peripheral surfaces of the hold pins 78 b abut theinner peripheral surface of the center hole 25 a of the reel plate 25,whereby this reel plate 25 is held with the plate surface being inintimate contact with an inner surface which is at a predeterminedposition on the metal mold 71. In this way, the movable metal mold 72 isclosed, and injection molding is performed by injecting resin from thegate 77 a.

[0191] In the reel 2 after molding, three hold traces 21 d in the formof a recess are formed in the bottom wall 21 a, integrally formed insidethe center hold 25 a of the reel plate 25, and at the center portion, agate trace 21 c is formed. In the holding by the hold pins 78 b, even ifthe hold pins 78 b are projected from the reel plate 25, the projectionhas little influence on the flow of resin injected from the gate 77 a.Therefore, the amount of projection of the hold pins 78 b may beincreased in order to enhance the function of holding the reel plate 25.

[0192] Next, FIG. 42 shows another embodiment of the metal mold. Thereel plate 25 placed on the stationary metal mold 71 is pressed andlocked by a movable pin 79, urged by a spring 80 provided in the movablemetal mold 72. In this locked state, injection molding is performed byinjecting resin.

[0193] This prevents the reel plates 25 from being moved by the flow ofresin at the time of injection, whereby molding of the reel 2 can beperformed with the reel plate 25 attached at a predetermined position.In addition, although a pin hole is formed in the reel bottom wall 21 aby the movable pin 79, it is closed by the reel plate 25 and thereforedust proof property can be assured. Note that in addition to the holdingof the reel plate 25 by the hold member 78 shown in FIG. 40B or 41B, thepressing and locking by the movable pin 79 may be performed.

[0194]FIG. 43 shows still another embodiment regarding the locking ofthe reel plate 25. In this example, the reel plate 25 is held in apredetermined position on the stationary metal mold 71 by magneticforce.

[0195] That is, a magnet 81 is disposed on the outer peripheral portionof the gate bush 77 of the stationary metal mold 25 so that it iscoplanar with the metal mold surface. The reel plate 25 is attracted andheld with the magnetic force of the magnet 81, and insert molding isperformed.

[0196] Next, various forms of reel plates 25, for enhancing the rigidattachment force of the reel 2 to the bottom wall 21 a, will be shown.

[0197] The reel plate 25 shown in FIG. 44A has a center hole 25 a. Also,three rigid-attachment holes 25 b are bored in the flat portion, andtaper portions 25 c such as those shown in FIG. 44B, or stepped portions25 d such as those shown in FIG. 44C, are formed over the respectivehalf peripheries of the outer peripheral portion, the inner peripheralportion of the center hole 25 a, and the inner peripheral portion of therigid attachment hole 25 b.

[0198] The insert molding of the aforementioned reel plate 25 isperformed with the surface of FIG. 44A being in intimate contact withthe inner surface of the stationary metal mold 71, and the taperportions 25 c or stepped portions 25 d are also filled with resin inorder to enhance the rigid attachment force of the reel plate 25,whereby the disengagement of the reel plate 25 from the reel isprevented. In addition, higher rigid attachment force is obtained byboring the rigid-attachment holes 25 b.

[0199] A center hole 25 a and rigid-attachment holes 25 b (three holes)are bored, in the reel plate 25 shown in FIGS. 45A and 45B, and taperportions 25 c are formed over the respective whole peripheries of theouter peripheral portion, the inner peripheral portion of the centerhole 25 a, and the inner peripheral portion of the rigid-attachment hole25 b.

[0200] A center hole 25 a and rigid-attachment holes 25 b (six holes)are bored, in the reel plate 25 shown in FIGS. 46A and 46B, and taperportions 25 c are formed over the respective whole peripheries of theinner peripheral portions of the rigid-attachment holes 25 b. Thedirections of the taper portions 25 c are alternated on three of theholes 25 b so that both sides of the reel plate 25 become symmetrical inshape, whereby interchangeability between both sides is provided. Thiseliminates the necessity for selecting the upper or lower side of thereel plate 25 when setting it to the metal mold 71, whereby operabilityis enhanced.

[0201] An annular groove 25 e is formed in the outer peripheral surfacein the reel plate 25 shown in FIGS. 47A and 47B. This groove 25 e isfilled with resin, whereby rigid attachment force increases.

[0202] Rigid attachment grooves 25 f in undercut form are formed in thesurface of the reel plate 25, shown in FIGS. 48A and 48B, which contactsresin. The rigid attachment grooves 25 f in undercut form are filledwith resin, whereby rigid attachment force increases.

[0203] Note that in the case where the rigid-attachment hole 25 b isbored in the reel plate 25, as previously described, the gate positionfor injection molding may be provided in the part of therigid-attachment hole 25 b.

[0204] Next, FIGS. 49 through 52 show various forms of the reel plate 25and the reel gear 24 formed in the outer periphery. In these forms, whenthe molded reel 2 is separated by the metal mold 71, the interferencebetween the gear portion metal mold for molding the reel gear 24 and thereel plate 25 is prevented.

[0205] The form shown in FIG. 49 forms a clearance (which is filled withresin) in the radial direction between the outer peripheral surface ofthe reel plate 25 and the inner peripheral end of the reel gear 24,thereby preventing the interference between the reel plate 25 and thegear portion metal mold when separating the mold from the plate.

[0206] The form shown in FIG. 50 forms a clearance in the heightdirection between the height position of the outer peripheral end of thereel plate 25 and the height of the tooth bottom portion of the reelgear 24, thereby preventing the aforementioned interference.

[0207] The form shown in FIG. 51 inclines the outer peripheral surfaceof the reel plate 25 and forms a clearance between the corner portion ofthe outer periphery of the reel plate 25 and the tooth bottom portion ofthe reel gear 24, thereby preventing the aforementioned interference.

[0208] The form shown in FIG. 52 chamfers the inner end portion of thegear portion metal mold, which molds the tooth bottom portion of thereel gear 24, and forms a clearance between the chamfered portion andthe outer peripheral end of the reel plate 25, thereby preventing theaforementioned interference.

[0209] According to this embodiment, as described above, for the insertmolding of the annular reel plate 25 having the center hole 25 a at thebottom surface of the reel 2, the hold trace 21 b or 21 d in the form ofa recess, which is formed by the hold member 78 of the metal moldholding the reel plate 25, is formed in the reel bottom wall 21 aclosing the center hole 25 a of the reel plate 25 with resin. Therefore,the holding of the reel plate 25 during insert molding can be reliablyperformed, and desired insert molding can be performed without movementof the reel plate 25 which is caused by the pressure and flow of resinat the time of injection molding. Also, there is no possibility that thereel plate 25 in the reel 2 after molding will project, and therefore,interference with other components can be prevented. In addition, thecenter hole 25 a is closed, whereby dust proof property can be easilyassured.

[0210] In addition, according to the aforementioned molding method, thereel plate 25 is held during insert molding by the movable pin 79provided in the metal mold, or by magnetic force. Therefore, the holdingof the reel plate 25 to the metal mold can be reliably performed withoutforming a through hole in the molded reel 2, and the reel plate 25 canbe formed integrally at a predetermined position on the reel 2.

[0211] Next, another embodiment of the insert molded portion of the reelplate 25 will be shown. FIG. 53A shows a bottom view of the reel plate25 of the bottom center portion of the reel 2 and FIG. 53B a sectionalview of the molded state.

[0212] The aforementioned reel plate is formed into an annular shapehaving a center hole 25 a. In the molded state with reel plate 25inserted into the bottom wall 21 a of the reel 2, the part of the centerhole 25 a is closed by the resin of the bottom wall 21 a, and outside anouter peripheral surface 25 g, a clearance 21 f in the form of acircumferential groove is formed between the outer peripheral surface 25g and the reel bottom wall 21 a surrounding this. Outside the clearance21 f, a reel gear 24 is provided.

[0213] Injection molding of the reel 2, as shown in FIG. 53B, isperformed by injecting resin into a cavity formed by a stationary metalmold 71 and a movable metal mold 72 through a gate 71 b. The stationarymetal mold 71 is provided with a ring protrusion 71 a for holding theouter peripheral surface of the reel plate 25. The outer peripheralsurface 25 g of the reel plate 25 is fitted into the inner peripheralsurface of the ring protrusion 71 a, and this reel plate 25 is held onan inner surface which is at a predetermined position on the metal mold71. The movable metal mold 72 is closed, and resin is injected.

[0214] In the reel 2 after molding, at the part of the bottom wall 21 aof the outer peripheral surface 25 g of the reel plate 25, a clearance21 f in the form of a circumferential groove, which results from thehold trace of the ring protrusion 71 a, is formed in recess form. Inaddition, a gate trace 21 c is formed in the center portion of thebottom wall 21 a that closed the center hole 25 a.

[0215] If insert molding is performed with the outer peripheral surface25 g of the reel plate 25 held by the above-mentioned ring protrusion 71a, the reel plate 25 can be prevented from moving and shifting out ofposition because of the flow of resin, and therefore, the reel plate 25can be rigidly attached at a predetermined position on the reel 2. Inaddition, because of formation of the clearance 21 f, the shrinkingforce resulting from the shrinkage of resin after insert molding willnot act on the outer peripheral surface 25 g and therefore deformationof the reel plate 25 can be suppressed.

[0216]FIG. 54 shows another embodiment of the reel plate 25.Reinforcement ribs 25 h are formed on the upper surface of the reelplate 25 that contacts the reel bottom wall 21 a. These reinforcementribs 25 h are formed by radial and ring ribs projecting from the platesurface. Note that the lower surface of the reel plate 25 which isexposed to the bottom surface of the reel 2 has no reinforcement rib andis provided flat. Also, the form of the reinforcement rib 25 h isdesigned and changed as appropriate, according to the required strength.

[0217] Such a reel plate 25 is insert-molded integrally with the reel 2,while it is being held by the aforementioned stationary metal mold 71(the ring protrusion 71 a is not always a necessity).

[0218] According to the form shown in FIG. 54, even if the bendingstrength of the reel plate 25 increases and the shrinking force of theresin forming the reel bottom wall 21 a after insert molding acts on thereel plate 25, the deformation will be suppressed by formation of thereinforcement ribs 25 h.

[0219] Next, FIG. 55 is a plan view showing another embodiment of thereel 2. As previously described, the reel plate 25 is rigidly attachedto the bottom surface of the bottom wall 21 a of the reel hub 21. In thebottom wall 21 a of the reel 2 which contacts the upper surface of thereel plate 25, recesses 29 are formed and resin contacting the uppersurface of the reel plate 25 is partially removed. That is, the surfaceof the aforementioned movable metal mold 72 is molded in contact withthe reel plate 25 so that the bottom wall 21 a is in an open state atthe parts of the recesses 29 and the upper surface of the reel plate 25is exposed to the bottom surfaces of the recesses 29.

[0220] Note that in formation of the recesses 29, the aforementionedgate 71 b is located at the center portion of the reel bottom wall 21 aand it is therefore necessary to form the recesses 29 with spaces sothat resin injected from this gate portion flows uniformly to each part,and particularly so that a flow in the radial direction is notdisturbed. In addition, the recesses 29 may be formed to reduce the wallthickness of the reel bottom wall 21 a.

[0221] According to the form shown in FIG. 55, the recesses 29 areformed in the reel bottom wall 21 a contacting the reel plate 25,whereby the amount of the resin contacting the reel plate 25 is reducedand the shrinking force of the resin after insert molding becomessmaller. As a result, deformation of the reel plate 25 can besuppressed.

[0222] According to this embodiment as described above, for the insertmolding by which the reel plate 25 for magnetic attraction is moldedintegrally to the bottom surface of the reel 2, a clearance is formedbetween the outer peripheral surface of the reel plate 25 and the reelbottom wall 21 a surrounding this. Therefore, no shrinking force actsfrom the outer peripheral surface to the center direction when resinafter insert molding is shrunk, deformation of the reel plate 25 can besuppressed and therefore a uniform clearance with the magnet can beassured. With formation of the clearance 21 f in the outer periphery ofthe reel plate 25, the reel plate 25 is held by the protrusion 71 a ofthe metal mold corresponding to this clearance 21 f, whereby positioningof the reel plate 25 during insert molding can be performed withreliability and desired insert molding can be performed without movementof the reel plate 25 that is caused by the pressure and flow of resin atthe time of injection molding.

[0223] In addition, in the example where the reinforcement ribs 25 h areprovided on the surface of the reel plate 25 which contacts the reelbottom wall 21 a, deformation of the reel plate 25, which is caused byan increase in the strength of the reel plate and the shrinking force ofresin when shrunk after insert molding, can be suppressed and thereforea uniform clearance with the magnet can be assured.

[0224] Furthermore, in the example wherein the bottom wall 21 a of thereel 2 contacting the reel plate 25 is partially removed, the shrinkingforce pulling the reel plate surface in the center direction, whichdevelops as resin shrinks after insert molding, is reduced. As a result,deformation of the reel plate 25 can be suppressed, whereby a clearancewith the magnet can be assured.

[0225] Next, an embodiment regarding formation of the tape reel will beshown. FIG. 56 is a sectional view of the reel and FIG. 57 an enlargedview of the essential part.

[0226] On the reel 1, a cylindrical reel hub 21 in which magnetic tapeis wound on the outer peripheral surface 21, and a lower flange portion22 projecting in disk form in the radial direction from the outerperiphery of one end portion (in the figure, lower end portion) of thisreel hub 21, are integrally formed from synthetic resin, and an upperflange portion 23 in the form of a disc, formed as a separate body bysynthetic resin, is rigidly attached to the other end portion of thereel hub 21 by an adhesive.

[0227] A disc bottom wall 21 a is continuous to the inner peripheralportion of the reel hub 21, and in the outside surface of this bottomwall 21 a, a reel gear 24 for driving the reel 1 to rotate is formed inring form. Furthermore, on the radially inner side from this real gear24, a real plate 25 for magnetic attraction, made of an annular metalplate, is inserted when molded.

[0228] Moreover, in the end surface of the reel hub 21 to which theupper flange portion 23 is rigidly attached, a stepped portion 56,recessed in ring form so that a portion on the side of the innerperipheral surface 21 h becomes lower in height, is formed as shown inFIG. 57. Also, the end surface 56 a of the stepped portion 56 in thisreel hub 21 and the end portion of the hub inner peripheral surface 21 hbecome adhesion surfaces.

[0229] On the other hand, the upper flange portion 23 has a circularopening at the central portion, and at the circumferential margin ofthis opening, a collar portion 57 is formed projecting in the directionperpendicular to a flange surface 23 a. As shown in FIG. 57, the cornerportion between this collar portion 57 and the flange surface 23 a isformed into an annular protruding portion 58 which fits on the steppedportion 56 of the reel hub 21. Also, the end surface 58 a (surfaceparallel with the flange surface 23 a ) of the annular protrudingportion 58 in this upper flange portion 23 and the outer peripheralsurface 57 a of the collar portion 57 become adhesion surfaces.

[0230] For the adhesion between the reel hub 21 and the upper flangeportion 23, an adhesive is supplied in a predetermined amount to theadhesion surface of the reel hub 21 and/or the adhesion surface of theupper flange portion 23 by supply means such as a dispenser, etc. Whileboth are being positioned, the collar portion 57 of the upper flangeportion 23 is inserted onto the inner peripheral surface 21 h of thereel hub 21, and the annular protruding portion 58 is fitted andassembled on the stepped portion 56. The outer peripheral surface 57 aof the flange collar portion 57 and the inner peripheral surface 21 h ofthe reel hub 21 are joined at a surface parallel (or may be inclined atan angle of about 1 to 100°) to the axis of rotation of the reel hub 21,and the end surface 58 a of the annular protruding portion 58 and theend surface 56 a of the stepped portion 56 a rejoined at a surfaceperpendicular to the rotation axis of the reel hub 21.

[0231] As the adhesive, a wide variety of adhesives are usable. However,it is preferable to use a light hardening type adhesive, particularly anultraviolet ray hardening type adhesive or a visible light hardeningtype adhesive. In the case of this light hardening type adhesive, theadhesive is applied to an adhesion surface and is then hardened byirradiating light (ultraviolet ray, visible light) for a predeterminedtime period (e.g., 5 sec). In this manner, the adhesion process ends.

[0232] The ultraviolet ray hardening type adhesive uses, for example, aknown one which has an acryloyl group to a few acryloyl groups as afunctional group and also has a composition that makes a radicalpolymerization reaction with a photo polymerized monomer, etc., byultraviolet rays and is bridged and polymerized. For instance, there are3-BONDs 3062, 3055, 3065 (3-Bond), ALONE-TIGHTs BU-130U, BU-230U,BU-249U (Toagosei), etc. The aforementioned ultraviolet ray hardeningtype adhesive may be equipped with a given hardening property such asanaerobic hardening, primer hardening, etc. These adhesives are hardenedin a few seconds to tens of seconds when irradiated with ultravioletrays of wavelength 200 to 400 nm. In this case it is preferred to moldthe upper flange portion 23 or reel hub 21 with transparent resin suchas polycarbonate(PC),polystyrene(PS),etc. However, resin does not alwaysneed to be transparent, because there is a type in which adhesionsurfaces are combined together after irradiation of ultraviolet rays.

[0233] As a visible light hardening type adhesive, there areALONE-TIGHTs VL-1303, VL-2303, VL-5303, etc. These can be used foradhesive even when the upper flange portion 23 or reel hub 21 issemitransparent or slightly colored.

[0234] In the above-mentioned embodiments, in order to enhance theadhesive strength of an adhesive, at least one of the adhesion surfacesin the adhesion portion between the end surface 56 a of the steppedportion 56 of the reel hub 21 and the end surface 58 a of the annularprotruding portion 58 in the upper flange portion 23 and the adhesionportion between the end portion of the hub inner peripheral surface 21 hand the outer peripheral surface 57 a of the collar portion 57 of theupper flange portion 23 is roughened as occasion demands. Roughening ofthis adhesion surface is obtained by roughening the surface of theadhesion-surface molding portion of the metal mold for the reel hub 21or upper flange portion 23, and it is preferable that the surfaceroughness be 1 μm or more in terms of Rz.

[0235] According to this embodiment, the reel hub 21 and the upperflange portion 23 are joined by an adhesive. As a consequence, adhesioncan be uniformly performed over the whole periphery without giving riseto deformation in the upper flange portion 23. The reel 1 after rigidattachment can be formed with dimensional precision corresponding tomolding precision. The upper flange portion 23 can be rigidly attachedperpendicular to the rotation axis of the reel hub 21. When this reel 1is being rotated to forward or rewind magnetic tape, the deflection ofthe rotation of the upper flange portion 23 is small and lateralfluctuation in magnetic tape being traveled is also small. Therefore,satisfactory positional precision is obtained, an influence on recordingand reproducing characteristics is small, and in addition, it becomespossible to meet the high-density requirement of the magnetic tapecartridge.

[0236] In addition, the adhesion between the reel hub 21 and the upperflange portion 23 is performed at a position away from the outerperipheral surface 21 g of the reel hub 21, and on the radially innerside from the stepped portion 56. As a result, the adhesive is preventedfrom overflowing from the adhesion surface to the part of the outerperipheral surface 21 g, and the influence of the adhesive on themagnetic tape that is wound on this outer peripheral surface 21 g can beeliminated.

[0237] Furthermore, if the adhesion surface is roughened, the adhesionarea to which an adhesive is applied is increased and the adhesivestrength is enhanced. As a result, the adhesion between the reel hub 21and the upper flange portion 23 can be more firmly performed, and theadhesion surface can endure an increase in the winding tension withoutincreasing the adhesion area.

[0238] Although, in the above-mentioned embodiment, adhesion isperformed at two surfaces perpendicular to each other in order to obtainhigh adhesive strength, at least the adhesion between the outerperipheral surface 57 a of the collar portion and the hub innerperipheral surface 21 h is necessary.

[0239]FIGS. 58 and 59 show a reel 2 according to another embodiment.This embodiment differs in the shape of the adhesion portion, and theother parts are provided in the same way as FIG. 56.

[0240] In the end surface of the reel hub 21 to which the upper flangeportion 23 is rigidly attached, an annular recess 59 is formed so that aportion on the side of the outer peripheral surface 21 g becomes lowerin height, as shown in FIG. 59. The end surface 59 a and peripheralsurface 59 b of this recess 59 become adhesion surfaces. On the otherhand, the upper flange portion 23 is in the form of a disc with acircular opening at the central portion, and as shown in FIG. 59, theinner peripheral surface 23 b and the radially inner portion of theinner flange surface 23 a become adhesion surfaces.

[0241] For the adhesion between the reel hub 21 and the upper flangeportion 23, an adhesive is supplied in a predetermined amount to theadhesion surface of the reel hub 21 and/or the adhesion surface of theupper flange portion 23 by supply means such as a dispenser, etc. Whileboth are being positioned, the inner peripheral portion of the upperflange portion 23 is fitted and assembled on the recess 59 of the reelhub 21. The inner peripheral surface 23 b of the upper flange portion 23and the peripheral surface of the recess 59 b of the reel hub 21 areadhered at a surface parallel to the axis of rotation of the reel hub21, and the end surface 59 a of the recess of the reel hub 21 and theradially inner portion of the flange surface 23 a are adhered at asurface perpendicular to the rotation axis of the reel hub 21.

[0242] In this embodiment, as with the above-mentioned embodiment, atleast one of the adhesion surfaces in the adhesion portion between therecess end surface 59 a of the reel hub 21 and the radially inner flangesurface 23 a of the upper flange portion 23 and the adhesion portionbetween the recess peripheral surface 59 b of the reel hub 21 and theinner peripheral surface 23 b of the upper flange portion 23 isroughened as occasion demands, thereby increasing the adhesive strengthof the adhesive.

[0243] According to this embodiment, as with the aforementionedembodiment, the reel hub 21 and the upper flange portion 23 are joinedby an adhesive. As a consequence, the reel hub 21 and the upper flangeportion 23 can be uniformly adhered over the whole periphery withoutgiving rise to deformation in the upper flange portion 23. Thedeflection of the rotation of the upper flange portion 23 is small andlateral fluctuation in magnetic tape being transported is also small.Furthermore, it becomes possible to meet the high-density requirement ofthe magnetic tape cartridge.

[0244] In addition, high adhesive strength is obtained by joining thereel hub 21 and the upper flange portion 23 at two surfacesperpendicular to each other. Furthermore, a stepped portion may beformed in the recess 59 of the reel hub 21.

[0245] Note that in both embodiments, the adhesion surface, in additionto being provided continuously on the whole periphery, may be formed ina discontinuous shape having a partial groove partially. In this case,an excess of adhesive can be more effectively prevented from flowing inthe groove and overflowing from the adhesion surface to the outside.

[0246] According to this embodiment as described above, the upper flangeportion 23 in the form of a disc is rigidly attached by an adhesive tothe end portion of the cylindrical reel hub 21 in which tape is wound onthe outer peripheral surface 21 g. As a result, the upper flange portion23 is rigidly attached so that it is at a right angle to the rotationaxis and deformation does not develop, whereby satisfactory dimensionalprecision can be obtained. By making the lateral deflection of woundtape smaller, even for resin molded products it becomes possible tosufficiently meet the enhanced recording density and recording precisionrequirements.

[0247] If a light hardening type adhesive, particularly an ultravioletray hardening type adhesive is used as the aforementioned adhesive, massproduction and process simplification can be achieved by a reduction inthe hardening time.

[0248] Furthermore, by employing an adhesive it is also possible tocombine the reel hub 21 and the upper flange 23, made of resin, whichcan not be welded by ultrasonic welding. Also, in ultraviolet welding,the flatness of the reel hub 21 and the cylindricality of the lowerflange portion 22 are reduced due to an unevenness in wall thicknessbetween the reel hub 21 and the lower flange portion 22 integrallyformed in order to assure weld surfaces, but uniform wall-thicknessmolding becomes possible. As a result, an enhancement in the moldingprecision of the reel hub 21 is achieved and the reel 2 with higherprecision is obtained.

[0249] In addition, all of the contents of Japanese Patent ApplicationNos. 10(1998)-158784, 10(1998)-202497, 10(1998)-158786, 10(1998)-160387,10(1998)-236935, 10(1998)-202498, 10(1998)-245308, 10(1998)-344984 and10(1998)-217432 are incorporated into this specification by reference.

1. A magnetic tape cartridge, for rotatably housing within a cartridgecase a single reel having magnetic tape wound thereon, comprisingreel-rotation restraining means for allowing rotation of said reel whenbeing used and restricting said rotation when not being used; whereinsaid reel-rotation restraining means has a restraining member forrestricting rotation of said reel by moving toward or away from saidreel, an urging member for urging said restraining member in arestraining direction, and a releasing member for moving saidrestraining member in a releasing direction, by rotating integrally withsaid reel and moving according to a chucking operation of drive-siderotation drive means; said reel is provided with a reel gear whichmeshes with a driving gear of said drive-side rotation drive means, anda pushing-up portion formed in part of said releasing member is providedso that a distal end thereof can abut said driving gear through athrough hole provided in said reel gear; and said through hole is boredbetween tooth edges of said reel gear.
 2. The magnetic tape cartridge asset forth in claim 1, wherein a recess engageable with a tooth edge ofsaid driving gear is formed in a distal end surface of said releasingmember which abuts said driving gear.
 3. A magnetic tape cartridge, forrotatably housing within a cartridge case a single reel having magnetictape wound thereon, comprising reel-rotation restraining means forallowing rotation of said reel when being used and restricting saidrotation when not being used; wherein said reel-rotation restrainingmeans has a restraining member for restricting rotation of said reel bymoving toward or away from said reel, an urging member for urging saidrestraining member in a restraining direction, and a releasing memberfor moving said restraining member in a releasing direction, by rotatingintegrally with said reel and moving according to a chucking operationof drive-side rotation drive means; said reel is provided with a reelgear which meshes a driving gear of said drive-side rotation drivemeans, and a pushing-up portion formed in part of said releasing memberis provided so that a distal end thereof can abut said driving gearthrough a through hole provided in said reel gear; and said pushing-upportion and said through hole contact each other through smallprotrusions which reduce the contact area.
 4. The magnetic tapecartridge as set forth in claim 1, 2, or 3, wherein the opposite toothedges of said reel gear between which said through hole is bored areremoved so that they become flat shapes, curved surface shapes, orchamfered surface shapes.
 5. A magnetic tape cartridge, for rotatablyhousing within a cartridge case a single reel having magnetic tape woundthereon, comprising reel-rotation restraining means for allowingrotation of said reel when being used and restricting said rotation whennot being used; wherein said reel-rotation restraining means has arestraining member for restricting rotation of said reel by movingtoward or away from said reel, an urging member for urging saidrestraining member in a restraining direction, and a releasing memberfor moving said restraining member in a releasing direction, by rotatingintegrally with said reel and moving according to a chucking operationof drive-side rotation drive means; said reel is provided with a reelgear which meshes with a driving gear of said drive-side rotation drivemeans, and a pushing-up portion formed in part of said releasing memberis provided so that a distal end thereof can abut said driving gearthrough a through hole provided in said reel gear; and said releasingmember is formed by sheet-metal pressing of a metal sheet.
 6. A magnetictape cartridge, for rotatably housing within a cartridge case a singlereel having magnetic tape wound thereon, comprising reel-rotationrestraining means for allowing rotation of said reel when being used andrestricting said rotation when not being used; wherein saidreel-rotation restraining means has a restraining member for restrictingrotation of said reel by moving toward or away from said reel, an urgingmember for urging said restraining member in a restraining direction,and a releasing member for moving said restraining member in a releasingdirection, by rotating integrally with said reel and moving according toa chucking operation of drive-side rotation drive means; said reel isprovided with a reel gear which meshes a driving gear of said drive-siderotation drive means, and a pushing-up portion formed in part of saidreleasing member is provided so that a distal end thereof can abut saiddriving gear through a through hole provided in said reel gear; and saidreel is provided with a guide member which guides part of said releasingmember in an inserting direction when inserting the pushing-up portionof said releasing member into said through hole.
 7. A magnetic tapecartridge, for rotatably housing within a cartridge case a single reelhaving magnetic tape wound thereon, comprising reel-rotation restrainingmeans for allowing rotation of said reel when being used and restrictingsaid rotation when not being used; wherein said reel-rotationrestraining means has a restraining member for restricting rotation ofsaid reel by moving toward or away from said reel, an urging member forurging said restraining member in a restraining direction, and areleasing member for moving said restraining member in a releasingdirection, by rotating integrally with said reel and moving according toa chucking operation of drive-side rotation drive means; said reel isprovided with a reel gear which meshes with a driving gear of saiddrive-side rotation drive means, and a pushing-up portion formed in partof said releasing member is provided so that a distal end thereof canabut said driving gear through a through hole provided in said reelgear; and the pushing-up portion of said releasing member is providednear each vertex of a generally triangular plate base.
 8. The magnetictape cartridge as set forth in claim 7, wherein the plate base of saidreleasing member is formed integrally with said pushing-up portion withhigh-rigidity resin material, while a sliding-contact portion, formedwith a separate member having a low friction characteristic, is rigidlyattached integrally to a center portion of an upper surface of said basewhich contacts a center portion of a lower surface of said restrainingmember.
 9. A magnetic tape cartridge, for rotatably housing within acartridge case a single reel having magnetic tape wound thereon,comprising reel-rotation restraining means for allowing rotation of saidreel when being used and restricting said rotation when not being used;wherein said reel-rotation restraining means has a restraining memberfor restricting rotation of said reel by moving toward or away from saidreel, an urging member for urging said restraining member in arestraining direction, and a releasing member for moving saidrestraining member in a releasing direction, by rotating integrally withsaid reel and moving according to a chucking operation of drive-siderotation drive means; said reel is provided with a reel gear whichmeshes with a driving gear of said drive-side rotation drive means, anda pushing-up portion formed in part of said releasing member is providedso that a distal end thereof can abut said driving gear through athrough hole provided in said reel gear; and gate traces for injectionmolding are provided near centers of rotation of said restraining memberand said releasing member.
 10. The magnetic tape cartridge as set forthin claim 9, wherein, in the releasing member which has the pushing-upportion and is formed by injection molding, such a bore which reduces awall thickness of said pushing-up portion is formed in the interior ofsaid pushing-up portion.
 11. A magnetic tape cartridge, for rotatablyhousing within a cartridge case a single reel having magnetic tape woundthereon, comprising reel-rotation restraining means for allowingrotation of said reel when being used and restricting said rotation whennot being used; wherein said reel-rotation restraining means has arestraining member for restricting rotation of said reel by movingtoward or away from said reel, an urging member for urging saidrestraining member in a restraining direction, and a releasing memberfor moving said restraining member in a releasing direction, by rotatingintegrally with said reel and moving according to a chucking operationof drive-side rotation drive means; said reel is provided with a reelgear which meshes with a driving gear of said drive-side rotation drivemeans, and a pushing-up portion formed in part of said releasing memberis provided so that a distal end thereof can abut said driving gearthrough a through hole provided in said reel gear; and said reel gear isdriven to rotate in mesh with a driving gear in which a tooth edgeportion thereof is formed into a curved surface.
 12. A magnetic tapecartridge, for rotatably housing within a cartridge case a single reelhaving magnetic tape wound thereon, comprising reel-rotation restrainingmeans for allowing rotation of said reel when being used and restrictingsaid rotation when not being used; wherein said reel-rotationrestraining means has a restraining member for restricting rotation ofsaid reel by moving toward or away from said reel, an urging member forurging said restraining member in a restraining direction, and areleasing member for moving said restraining member in a releasingdirection, by rotating integrally with said reel and moving according toa chucking operation of drive-side rotation drive means; said reel isprovided with a reel gear which meshes a driving gear of said drive-siderotation drive means, and a pushing-up portion formed in part of saidreleasing member is provided so that a distal end thereof can abut saiddriving gear through a through hole provided in said reel gear; and atooth edge portion of said reel gear is formed into a curved surface.13. A magnetic tape cartridge, for rotatably housing within a cartridgecase a single reel having magnetic tape wound thereon, comprisingreel-rotation restraining means for allowing rotation of said reel whenbeing used and restricting said rotation when not being used; whereinsaid reel-rotation restraining means has a restraining member forrestricting rotation of said reel by moving toward or away from saidreel, an urging member for urging said restraining member in arestraining direction, and a releasing member for moving saidrestraining member in a releasing direction, by rotating integrally withsaid reel and moving according to a chucking operation of drive-siderotation drive means; said reel is provided with a reel gear whichmeshes with a driving gear of said drive-side rotation drive means, anda pushing-up portion formed in part of said releasing member is providedso that a distal end thereof can abut said driving gear through athrough hole provided in said reel gear; and said reel is formed bymolding a metal reel plate on a bottom surface thereof by insertmolding, and said reel is molded by a metal mold in which a hold memberfor holding an inner peripheral surface of said reel plate is disposedon an outer periphery of a gate.
 14. A magnetic tape cartridge, forrotatably housing within a cartridge case a single reel having magnetictape wound thereon, comprising reel-rotation restraining means forallowing rotation of said reel when being used and restricting saidrotation when not being used; wherein said reel-rotation restrainingmeans has a restraining member for restricting rotation of said reel bymoving toward or away from said reel, an urging member for urging saidrestraining member in a restraining direction, and a releasing memberfor moving said restraining member in a releasing direction, by rotatingintegrally with said reel and moving according to a chucking operationof drive-side rotation drive means; said reel is provided with a reelgear which meshes a driving gear of said drive-side rotation drivemeans, and a pushing-up portion formed in part of said releasing memberis provided so that a distal end thereof can abut said driving gearthrough a through hole provided in said reel gear; and said reel isformed by molding a metal reel plate on the inner peripheral side ofsaid reel gear by insert molding, and said reel is molded by a metalmold provided with a means of preventing interference between agear-portion metal mold for molding said reel gear and said reel plate.15. A magnetic tape cartridge, for rotatably housing within a cartridgecase a single reel having magnetic tape wound thereon, comprisingreel-rotation restraining means for allowing rotation of said reel whenbeing used and restricting said rotation when not being used; whereinsaid reel-rotation restraining means has a restraining member forrestricting rotation of said reel by moving toward or away from saidreel, an urging member for urging said restraining member in arestraining direction, and a releasing member for moving saidrestraining member in a releasing direction, by rotating integrally withsaid reel and moving according to a chucking operation of drive-siderotation drive means; said reel is provided with a reel gear whichmeshes with a driving gear of said drive-side rotation drive means, anda pushing-up portion formed in part of said releasing member is providedso that a distal end thereof can abut said-driving gear through athrough hole provided in said reel gear; and said reel is formed bymolding a metal reel plate by insert molding, and said reel is alsoformed so that outside the outer peripheral surface of said reel plate,a clearance in the form of a circumferential groove is formed betweensaid outer peripheral surface and a bottom wall of said reel, and sothat outside said clearance, said reel gear is formed.
 16. A magnetictape cartridge, for rotatably housing within a cartridge case a singlereel having magnetic tape wound thereon, comprising reel-rotationrestraining means for allowing rotation of said reel when being used andrestricting said rotation when not being used; wherein saidreel-rotation restraining means has a restraining member for restrictingrotation of said reel by moving toward or away from said reel, an urgingmember for urging said restraining member in a restraining direction,and a releasing member for moving said restraining member in a releasingdirection, by rotating integrally with said reel and moving according toa chucking operation of drive-side rotation drive means; said reel isprovided with a reel gear which meshes with a driving gear of saiddrive-side rotation drive means, and a pushing-up portion formed in partof said releasing member is provided so that a distal end thereof canabut said driving gear through a through hole provided in said reelgear; and said reel is formed by molding a metal reel plate by insertmolding, and said reel is also formed so that a reinforcement rib isformed on a surface of said reel plate which contacts a bottom wall ofsaid reel.
 17. A magnetic tape cartridge, for rotatably housing within acartridge case a single reel having magnetic tape wound thereon,comprising reel-rotation restraining means for allowing rotation of saidreel when being used and restricting said rotation when not being used;wherein said reel-rotation restraining means has a restraining memberfor restricting rotation of said reel by moving toward or away from saidreel, an urging member for urging said restraining member in arestraining direction, and a releasing member for moving saidrestraining member in a releasing direction, by rotating integrally withsaid reel and moving according to a chucking operation of drive-siderotation drive means; said reel is provided with a reel gear whichmeshes with a driving gear of said drive-side rotation drive means, anda pushing-up portion formed in part of said releasing member is providedso that a distal end thereof can abut said driving gear through athrough hole provided in said reel gear; and said reel is formed bymolding a metal reel plate by insert molding, and said reel is alsoformed so that a recess is formed in a bottom wall of said reel whichsaid reel plate contacts.
 18. A magnetic tape cartridge, for rotatablyhousing within a cartridge case a single reel having magnetic tape woundthereon, comprising reel-rotation restraining means for allowingrotation of said reel when being used and restricting said rotation whennot being used; wherein said reel-rotation restraining means has arestraining member for restricting rotation of said reel by movingtoward or away from said reel, an urging member for urging saidrestraining member in a restraining direction, and a releasing memberfor moving said restraining member in a releasing direction, by rotatingintegrally with said reel and moving according to a chucking operationof drive-side rotation drive means; said reel is provided with a reelgear which meshes with a driving gear of said drive-side rotation drivemeans, and a pushing-up portion formed in part of said releasing memberis provided so that a distal end thereof can abut said driving gearthrough a through hole provided in said reel gear; and said reel isformed by joining a reel hub and an upper flange portion by adhesion,and said reel is formed so that said upper flange portion is providedwith a collar portion which fits onto an inner peripheral surface ofsaid reel hub, an annular protruding portion is formed between saidcollar portion and a surface of said upper flange portion, and so thatan end surface of said annular protruding portion and an outerperipheral surface of said collar portion are adhered to said reel hubas adhesion surfaces.